Ankylosing Spondylitis and Psoriasis: What Is Their Relationship?

People with one autoimmune disease are likely to develop another autoimmune condition, including those with ankylosing spondylitis (AS) and psoriasis.

Autoimmune diseases occur when the immune system malfunctions and attacks healthy tissues. With AS, the malfunctioning immune system attacks the spine, and with psoriasis, these attacks focus on skin cells.

Ankylosing spondylitis is a type of autoimmune spondyloarthritis affecting the spine and leading to vertebrae fusing. The earliest signs of AS are pain and stiffness in the low back and hips.

AS needs aggressive and ongoing treatment to prevent complications like joint and spinal damage, osteoporosis (progressive bone thinning), spinal fractures, heart disease, eye inflammation, and cauda equina syndrome (the compression of the spinal nerve roots, which can lead to incontinence or paralysis).

Psoriasis is an autoimmune skin condition that causes scaly, red, and silvery skin patches called plaques. Psoriasis can be a distressing and complicated condition that affects more than just the skin. It causes a painful rash throughout the body and systemic symptoms like fever and fatigue during flare-ups.

If the inflammation goes uncontrolled, psoriasis can lead to more serious problems, including other autoimmune diseases, diabetes, heart disease, and mental health conditions like depression and anxiety. 

Psoriasis is also linked to psoriatic arthritis (PsA). PsA is a type of spondyloarthritis because it can cause inflammation of the spine and sacroiliac joints in the pelvis. About 40% of people with psoriasis will develop PsA within five to 10 years of the onset of psoriasis.

This article discusses the relationship between ankylosing spondylitis and psoriasis. It will also cover how to treat and manage the conditions together.

Connection Between Ankylosing Spondylitis and Psoriasis 

Spondyloarthritis (SpA) is an umbrella term for inflammatory conditions of the spine. SpA includes autoimmune arthritis conditions like axial spondyloarthritis (ax-SpA), PsA, reactive arthritis, and spondyloarthritis associated with inflammatory bowel disease. Ax-SpA has two subtypes: AS and non-radiographic axial spondyloarthritis (nr-axSpA, a precursor to AS). 

PsA is a subtype SpA of skeletal involvement and psoriasis. PsA with spine involvement is sometimes called axial PsA or psoriatic spondylitis. Psoriasis can also appear with other SpA types, including AS, often before a SpA diagnosis.

Psoriasis affects about 10% of people with AS. The overlapping nature of AS, PsA, and psoriasis can confuse healthcare providers. This has led researchers to work toward a better understanding of whether people diagnosed with AS and psoriasis had PsA spine involvement instead of AS.

Researchers at the University of Toronto compared people with AS and psoriasis to those with axial PsA and psoriasis. The study consisted of three groups—one group with both AS and psoriasis, one group with axial PsA, and a third group with AS only.  

Here, researchers came to three conclusions:

1. Axial PsA was different demographically (whom it affects by age and sex) compared to AS with and without psoriasis. 
2. Axial PsA is associated with worse peripheral arthritis (arthritis of the large joints—in the arms, legs, knees, etc.) and less back pain.
3. Axial PsA and AS with psoriasis appear to be two different diseases.
   

Ankylosing Spondylitis and Psoriasis Risks

Psoriasis and AS share some risk factors, which might explain why these two conditions sometimes coexist. However, that risk points to environmental risk factors, such as smoking or infections, and not necessarily genetic risk factors because of the link between each disease and a genetic mutation. 

AS is common in people with the HLA-B27 genetic marker. HLA-B27 positivity in people with AS is 85%.

HLA-Cw6 is the most substantial genetic risk factor for psoriasis. It is also linked to disease course, symptoms, severity, coexisting conditions, and treatment outcomes. 

Some risk factors for AS might overlap with psoriasis risk factors. AS risk factors include: 

• A family history of AS: HLA-B27 tends to run in families. But having the HLA-B27 gene doesn't mean someone will develop AS, and it is possible not to have the mutated gene and get AS.
• Age: A diagnosis of AS usually occurs in middle age and before age 45, but children and teens can also have AS.
• Sex: Though the prevalence of HLA-B27 is equal among people of any sex, people identified as male at birth are more likely to be diagnosed with AS. Male sex is also considered to risk factor for progression from nr-axSpA to AS. Though males are more likely to be diagnosed with AS, the disease burden for females with AS is much higher due to delays in diagnosis, higher disease activity, and reduced responses to biologic drug therapies.
• Having another autoimmune disease: If you have another autoimmune disease, like psoriasis, your risk for AS increases.
• Altered gut microbiota (the community of bacteria that normally inhabit the intestines).
• Infections: These include Klebsiella pneumoniae, respiratory tract infections, and tonsillitis (infection of the tonsils), especially in childhood.
• Mechanical stress: This stress occurs in body tissues and is responsible for musculoskeletal conditions.
• Smoking: Some researchers believe smoking is linked to the development of AS but are unsure how it causes the disease. Smoking might also worsen symptoms of AS and increase disease progression. 
  

Psoriasis risk factors include:

• Skin injuries: Psoriasis can be triggered after a skin break injury from vaccinations, sunburns, scratches, or other skin breaks.
• Drugs: Certain medications are linked to triggering the development of psoriasis, including lithium (for treating bipolar disorder), anti-malarial drugs, beta-blockers (for treating blood pressure), quinidine (for treating irregular heartbeats), and Indocin (indomethacin) (for treating arthritis pain).
• Viral and bacterial infections: Upper respiratory infections and strep throat especially raise the risk.
• Family history: You have a higher risk for psoriasis if one or both of your parents have psoriasis. According to the National Psoriasis Foundation, you have about a 10% risk if one parent has psoriasis and a 50% increased risk if both parents have it.
• Smoking and alcohol consumption: Both smoking and alcohol consumption have been linked to the development of psoriasis.

According to the National Psoriasis Foundation, psoriasis is more frequently diagnosed in White Americans. It can also affect Black and Hispanic Americans, but it is diagnosed more than 50% less in these two groups. This may be due to underdiagnosis rather than true prevalence.

Having both AS and psoriasis might lead to worsening symptoms of both conditions, but it is unknown whether either disease increases the risk for the other.

For example, a 2022 study published in RMD Open found psoriasis was frequent in early ax-SpA but did not note whether having psoriasis increased AS risk. Researchers did find that people with ax-SpA conditions with psoriasis had more swollen joints over time and were using more biologic drug therapies. However, they did not have worse ax-SpA disease severity and activity. 

Treatment and Management of Ankylosing Spondylitis and Psoriasis 

There are no cures for AS or psoriasis, but both conditions are manageable and treatable. Treatment for AS and psoriasis can sometimes overlap, and some treatments that manage AS can also relieve psoriasis symptoms.

Ankylosing Spondylitis

Treating AS aims to relieve symptoms and delay or prevent spine damage. This typically involves a combination of exercise, physical therapy, and medicine. Some people might need surgery to repair spine damage caused by AS. 

Exercise and Physical Therapy

Keeping active can help improve your posture and range of movement in your spine. It might also help prevent spine pain and stiffening. A physical therapist can advise you on the most effective exercises for managing AS and create an exercise program that meets your unique situation.

Medicine 

Medication for psoriasis can manage symptoms and pain and prevent worsening symptoms and disease complications. 

• Pain relievers: Your healthcare provider might recommend or prescribe pain relievers to help you manage AS pain from flare-ups and as treatment calms symptoms. Over-the-counter (OTC) pain relievers like Advil (ibuprofen) and Aleve (naproxen) might also help bring down inflammation. Your healthcare provider can prescribe more potent pain relievers like Voltaren (diclofenac) to treat pain when OTC treatments have not helped. 
  
• Corticosteroids: Corticosteroids can be given as tablets and injections to manage and bring down inflammation from AS. Due to their possible side effects, these drugs can only be offered for short periods. Injections can only be taken twice a year. Side effects include an increased risk of severe and life-threatening infections, injection site reactions, and a higher risk of osteoporosis.  
  
• Disease-modifying anti-rheumatic drugs (DMARDs): DMARDs are prescribed to people with AS who experience pain and inflammation in joints other than the spine. Azulfidine (sulfasalazine) and methotrexate are the main DMARDs prescribed for treating inflammation affecting other joints of the body, including the large joints of the arms and legs.
  
• Biologics: Food and Drug Administration-approved biologics for treating ankylosing spondylitis include tumor necrosis factor (TNF) inhibitors Enbrel (etanercept), Cimzia (certolizumab), Remicade (infliximab), Simponi (golimumab), and interleukin inhibitors Cosentyx (secukinumab) and Taltz (ixekizumab). These can be taken as injections or intravenous (IV) infusions. Biologic drugs work to suppress immune system activity, which can reduce AS disease activity and symptoms. Biologics might also help to slow down disease progression.
• Janus kinase inhibitors: These drugs inhibit enzymes that promote inflammation. Rinvoq (upadacitinib) may be taken for ankylosing spondylitis and/or active psoriatic arthritis when TNF inhibitors did not work well or weren't tolerated.
  

Surgery 

Most people with AS will never need surgery, but surgery might be an option for people who experience spinal deformities or joint problems. The surgery your healthcare provider will recommend will depend on the affected joints or spine areas, symptoms, and overall health.

Psoriasis

The goal of psoriasis treatment is to stop skin cells from growing too quickly and manage skin symptoms. Your options include topical therapies, light therapy, and oral and injected medicines.

What treatments your healthcare provider recommends and prescribes will depend on the severity of psoriasis and how responsive other therapies have been. You might need to try different therapies or a combination before you find something that works. 

Topical Therapies 

Different topical therapies can help reduce skin rash and skin cell growth, manage itch and skin pain, and remove scales.

Corticosteroids are the most commonly prescribed topical treatments for treating psoriasis and are available as ointments, lotions, gels, and creams. Some are available OTC, while others are prescribed by your healthcare provider.

Additional topical medicines for treating psoriasis include: 

• Vitamin D analogs
• Retinoids
• Calcineurin inhibitors such as Protopic (tacrolimus ointment) and Elidel (1.0% pimecrolimus cream)
• Coal tar
• Salicylic acid
• Anthralin
  

Light Therapy

Light therapy is considered a first-line treatment for moderate to severe psoriasis alone or with other therapies. Light therapy involves exposing psoriasis-affected skin to controlled amounts of natural or artificial light. You will need multiple treatments to see results. 

Your options for light therapy include: 

• Sunlight 
• UVB and UVA narrowband
• Goeckerman therapy, for treating moderate to severe plaque psoriasis using crude coal tar and artificial ultraviolet radiation
• Psoralen plus UVA
• Excimer laser
  

Oral and Injected Medicines 

For people with moderate to severe psoriasis, your healthcare provider can prescribe oral or injected medicines when other treatments have not worked. Some of these might be given for short periods until symptoms improve, while others are given long term. They include;

• Oral corticosteroids: Your healthcare provider might prescribe an oral corticosteroid to help bring a severe skin flare-up. 
• Retinoids: These oral medicines can reduce the production of skin cells.
• Biologics: If you are not already taking a biologic to manage AS, your healthcare provider can prescribe a biologic drug to alter your immune system and disrupt the disease cycle that causes the overgrowth of skin cells. Some biologics that treat both psoriasis and AS are Enbrel, Remicade, Humira, Cosentyx, and Cimzia. Additional biologics approved to treat psoriasis include Otzela (apremilast), Taltz (ixekizumab), Tremfya (guselkumab), and Skyrizi (risankizumab-rzaa).
• DMARDs: Methotrexate and cyclosporine are the two most commonly prescribed DMARDs for psoriasis. They can be given as monotherapies (single therapies) or in combination with biologics or other psoriasis therapies. Both are safe and effective for most people and can help decrease skin cell production and suppress inflammation.
  

Management of Both Diseases

If you have AS with psoriasis, you will need to manage and treat these diseases simultaneously and effectively because both result from an overactive immune system. If one disease is active, chances are so is the other. 

AS can be an aggressive condition. Left untreated, it can lead to severe complications, including spine fusion. Both psoriasis and AS can increase your risk for other severe health conditions, including heart disease.

Be sure to keep all appointments with your doctor and reach out for any changes in symptoms or if AS and psoriasis treatments are not helping.  

Summary  

Ankylosing spondylitis and psoriasis are autoimmune diseases in which the immune system malfunctions and attacks healthy tissues. With AS, the attacks focus on the spine, and with psoriasis, the attacks are on the skin. Though it is rare, AS and psoriasis can coexist, and research shows psoriasis often comes before AS.

Both AS and psoriasis have genetic causes but result from different gene mutations. Both run in families, which means if you have close relatives with either condition, your risk for that disease is higher. Other risk factors for AS and psoriasis are infections, stress, smoking, and alcohol consumption. 

Treatments for AS and psoriasis might overlap as well. Medicines that treat both conditions are biologic drug therapies, DMARDs, and corticosteroids. 

If you have psoriasis and start to experience signs of AS, including low back and hip pain, you should immediately inform your healthcare provider because AS will get worse over time. You should also report a skin rash or other skin symptoms if you have AS.

A Word From Verywell 

It is not unusual for people with one autoimmune disease to develop additional autoimmune conditions years later. Though experts do not know what causes the immune system to attack itself, they do know that autoimmune disorders can affect many tissues and organs throughout the body. 

If you have an autoimmune disease, like ankylosing spondylitis or psoriasis, you should watch out for additional symptoms that are inconsistent with your condition. Symptoms such as inflammation in any body area, especially the joints, fever, nerve pain, or balance issues should be reported. Your healthcare provider can run tests and determine the cause.